| Housebuilding People Ltd | Administrative & support | 2018 |
| Housedeal Limited | Real estate | 1987 |
| Housekeeping Heroes Ltd | Other services | 2020 |
| Hovarian Ltd | Hospitality | 2025 |
| Hovercrest Limited | Households | 1983 |
| HOW Green Ltd | Professional & scientific | 2025 |
| Howard Estate Agency LLP | | 2012 |
| Howard Overman Limited | Arts & recreation | 2003 |
| Howarth Brackin Limited | Wholesale & retail | 2014 |
| Howell Roofing Services Limited | Construction | 2014 |
| Howie Technology Limited | Manufacturing | 2012 |
| Howkins & KAY Ltd | Real estate | 2020 |
| HP Projects Limited | Construction | 2021 |
| HPL Club Limited | Health & social care | 2025 |
| HPU Investments Limited | Real estate | 2021 |
| HQ Blinds and Shutters Ltd. | Manufacturing | 2021 |
| HR Bespoke Consultancy Ltd | Administrative & support | 2025 |
| HR Industries Limited | Information & communication | 2005 |
| HR42 Ltd. | Professional & scientific | 2012 |
| HRH Developments Limited | Real estate | 2016 |
| HT Servo Ltd | Wholesale & retail | 2001 |
| HTA Housing Ltd | Real estate | 2022 |
| Hub Software Engineering Limited | Information & communication | 2009 |
| Hublee Ltd | Information & communication | 2026 |
| Hugo Forbes Limited | Financial services | 2017 |
| Hugo's Studio Ltd | Professional & scientific | 2015 |
| Human Nature Studios Limited | Information & communication | 2010 |
| Humanity Squared Ltd | Professional & scientific | 2019 |
| Humber Avenue Community Allotments Community Interest Company | Other services | 2021 |
| Hummingbird Electrics Ltd | Construction | 2021 |
| Humphrey Electrical Solutions Limited | Construction | 2024 |
| Hundoss Ltd | Professional & scientific | 2020 |
| Hungry X Ltd | Professional & scientific | 2023 |
| Hunseb Ltd | Administrative & support | 2022 |
| Hunt Visuals Ltd | Information & communication | 2024 |
| Hunter Development Holdings Limited | Construction | 1998 |
| Hunter Developments (Southern) Limited | Professional & scientific | 1994 |
| Hunters Recruitment & Training Limited | Administrative & support | 2009 |
| Huntsmans Dog and Cat Hotel Ltd | Agriculture & fishing | 2017 |
| Hurst Avenue Freehold Limited | Households | 2020 |
| Hurston Estates (North East) Limited | Real estate | 1987 |
| Hurston Estates Limited | Real estate | 1986 |
| Hurston House Investments Limited | Real estate | 2010 |
| Hurston Property Investment Limited | Real estate | 2020 |
| Hurston Real Estate (Barry) Limited | Real estate | 2025 |
| Hurston Real Estate Limited | Real estate | 2016 |
| Husky 1965 Ltd | Administrative & support | 1965 |
| HW Estate Agents Ltd | Real estate | 2012 |
| HW Estate Agents Worthing Ltd | Real estate | 2022 |
| HW Works Limited | Real estate | 2015 |
| HWF Laminating Limited | Manufacturing | 2023 |
| Hwyl Wellbeing and Yoga Limited | Education | 2024 |
| Hxbx Limited | Administrative & support | 2020 |
| Hyde END Enterprises LLP | | 2021 |
| Hyde END Investments Limited | Financial services | 2025 |
| Hydrospas Ltd | Wholesale & retail | 2024 |
| Hyett Homes Limited | Real estate | 2010 |
| Hypha Recruit Ltd | Administrative & support | 2013 |
| I AM Geek Ltd | Information & communication | 2023 |
| I C Worthing Limited | Hospitality | 2020 |
| I Tech Centre Limited | Other services | 2019 |
| I.D. Beauty Dppc UK Limited | Wholesale & retail | 2018 |
| I.D. Beauty International Distribution Limited | Wholesale & retail | 2005 |
| Iamsport Limited | Wholesale & retail | 2025 |
| IAN Burke Contracting Limited | Information & communication | 2026 |
| IAN Daniels Services Limited | Construction | 1988 |
| IAN Jones Consulting Limited | Professional & scientific | 2024 |
| IAN Watkins Estate Agents Ltd | Real estate | 2014 |
| IB Flooring Limited | Construction | 2013 |
| Ibgn Franchising Limited | Professional & scientific | 2023 |
| Ibmakay Ltd | Health & social care | 2022 |
| Ibot Entertainment Limited | Professional & scientific | 2014 |
| Ibot Holdings Limited | Financial services | 2022 |
| IC Autocare Ltd | Wholesale & retail | 2015 |
| Ice House Music Limited | Arts & recreation | 2007 |
| Icenet Limited | Information & communication | 1997 |
| ICW Digital Limited | Information & communication | 2016 |
| Ideabcn Design & Management Limited | Professional & scientific | 2015 |
| Ideal IT Sussex Ltd | Other services | 2023 |
| Ideasun Limited | Manufacturing | 2000 |
| Idieal Marketing Private Limited | Wholesale & retail | 2022 |
| IDK Investments Ltd | Administrative & support | 2023 |
| Idkem Investments Ltd | Financial services | 2023 |
| IEP Financial (Hove) Ltd | Financial services | 2020 |
| Ifcon Limited | Information & communication | 2005 |
| IG Protect Limited | Administrative & support | 2018 |
| Ignite Sales and Marketing Limited | Administrative & support | 2003 |
| Iguard Detection Limited | Administrative & support | 2012 |
| IHW Advisory Ltd | Professional & scientific | 2023 |
| Ikon Films Ltd | Information & communication | 2016 |
| Ilex Inns Limited | Hospitality | 2014 |
| Ilex Networks Ltd | Information & communication | 2025 |
| Ilium Ltd | Health & social care | 2006 |
| Illusions 2 Limited | Other services | 2010 |
| Iloveairfryers Limited | Other services | 2021 |
| Imara Beauty Ltd | Information & communication | 2023 |
| Immolnay UK Limited | Real estate | 2022 |
| IN the Hoods Ltd | Administrative & support | 2001 |
| IN Your Defence Ltd | Professional & scientific | 2012 |
| Inanutshell Consulting Limited | Professional & scientific | 2021 |